1. Field of the Invention
The present invention relates generally to printing presses and more particularly to wipe holders for wipes for printing press bearers.
2. Background Information
Rotary printing presses have rotating cylinders for printing sheets or a web of material, such as paper.
When two cylinders next to each other run in a certain relationship to one another, for example 1:1, bearers often are provided at the end of the cylinders. For example, on an offset lithographic printing press, a plate cylinder bearer at the end of a plate cylinder can be in rolling contact with a blanket cylinder bearer at the end of the blanket cylinder. The bearers help ensure smooth rolling contact between the two cylinders.
The rolling surfaces of the bearers however often become fouled or contaminated, for example by printing inks and paper waste. Thus it has been known to provide wipes to wipe the rolling surfaces of the bearers. These wipes typically have been held by a wipe holder similar to a clip. The holder often provides an insufficient hold on the wipe and allows the wipe to lose contact with the bearer. The wipe can be knocked out of place or skew easily. The pressure applied to the bearer also is dependent upon the wipe material stiffness. In addition, a tool such as a screw driver is required to release the clip.
An object of the present invention is to provide a bearer holder capable of holding the wipe firmly in place. Another alternate or additional object of the present invention is to provide a bearer wipe holder which does not permit skewing of the wipe. Yet another alternate or additional object of the present invention is to provide a holder which can be adjusted to compensate for different wipe material stiffness. Another alternate or additional object of the present invention is to eliminate the need for a tool to change wipes.
The present invention thus provides a bearer wipe holder comprising a base and a fastener selectively removable from the base, a wipe fitting between the base and the fastener, the fastener contacting the base through the wipe at least separate two locations when the wipe is between the base and the fastener.
By providing contact between the base and the fastener through the wipe at at least two separate locations, the wipe can be held firmly between the fastener and the base and be prevented from skewing.
Preferably, the base and the fastener are connected by at least two pins and a bolt. The pins preferably are fixed to at least one of the fastener and the base, and interact with holes in the other of the fastener and the base. The bolt preferably is a rotatably connected to the base, and is spring-loaded toward the base by a spring in the base operating on a knob at the base end of the bolt. The fastener preferably has an aperture through which a part of the bolt head can fit when the bolt is in a first rotational position, so that the fastener can permit replacement of the wipe. In a second rotational position, the bolt head tightly holds the wipe between the fastener and the base through contact of the wipe with a contact surface of the bolt head. The bolt can be rotated by hand by pulling against the spring force. Preferably a quarter turn of the bolt can provide for the fastener to be in a release or a fastening position.
The present invention also provides a bearer wipe comprising a felt body having at least a first hole for receiving a pin of a wipe holder and a second hole or slot for receiving one of a second pin and a bolt of a bearer holder. Preferably, the bearer wipe further includes a third hole or slot for receiving the other one of the second pin and the bolt.
The wipe preferably is made of felt and may be for example {fraction (3/16)} ths of an inch thick.
The present invention also provides a method for wiping a bearer of a printing press comprising the steps of:
placing a wipe against a base of a bearer holder; and
placing a fastener over the wipe so that the fastener contacts the base through the wipe at at least two separate locations so as to firmly hold the wipe between the base and the fastener.
Preferably, the method further includes using a rotatable bolt to tighten the fastener with respect to the base and the wipe.
In a preferred embodiment, the method includes the steps of placing a wipe over a base of a bearer holder having two holes, aligning two wipe holes with the two holes, placing a wipe fastener with two pins over the wipe so that the two pins fit through the two wipe holes into the two holes. The fastener may then be fastened to hold the wipe tightly, preferably by a rotatable bolt.
The base of the wipe holder preferably is rotatably supported through a pin to permit for an adjustment of the contact angle of the wipe and the bearer. In this way, pressure against the bearer can be changed to compensate for different wipe stiffnesses.